The United States and Japan will step up their defence cooperation to deal with the threat from nuclear-armed North Korea as tensions in East Asia remain high, officials from the two allies said on Thursday.

Greste outrage at prison sentence

Australian journalist Peter Greste says he is devastated and outraged by the seven-year jail sentence handed down to him by a Egyptian court.

In a message posted on Facebook by his brothers Mike and Andrew after a prison visit, Greste says he will consider all possible measures to have the conviction overturned.

"Throughout this trial, the prosecutor has consistently failed to present a single piece of concrete evidence to support the outrageous allegations against us," he says in the statement.

"The verdict confirms that our trial was never simply about the charges against us. It has been an attempt to use the court to intimidate and silence critical voices in the media."

Greste, and his Al Jazeera colleagues Mohamed Fahmy and Baher Mohamed, were found guilty on Monday of reporting false news in the wake of the 2013 coup that ousted Islamist president Mohamed Morsi.

They were also convicted of supporting Morsi's Muslim Brotherhood, which was declared a terrorist organisation after the coup.

Their jailing has sparked worldwide outrage, with US Secretary of State John Kerry labelling the verdict "chilling and draconian" and Prime Minister Tony Abbott saying he was bewildered by the decision.